Simonson is an attorney who previously served as special counsel to the secretary and deputy general counsel at HHS. Before joining the department, he was corporate secretary and counsel for Amtrak.

In the 1990s, Simonson worked for then-Wisconsin Gov. Tommy G. Thompson — who later became HHS secretary from 2001 to 2005 — as legal counsel, directing crime and corrections policy development and coordinating the state’s public safety agencies, according to his online biography.

According to several experts Simonson's lack of technical and scientific expertise is harming HHS's efforts. Michael Greenberger, director of the University of Maryland’s Center for Health and Homeland Security, told CQ, “...the whole vaccine program is floundering in the absence of any sophisticated medical and scientific leadership.” An anonymous industry official also said of Simonson, “He doesn’t understand product development cycles [or] product risk. When he’s making decisions, it’s based on information he’s getting from third parties, but he’s not independently able to validate if what he’s doing is right.”